1. Field
The present invention relates to radiation detectors, and more particularly relates to a solid state radiation detector with improved gamma radiation sensitivity.
2. Related Art
Conventional neutron detectors typically include devices which operate as ionization chambers or proportional counters, both of which use a neutron active gas such as BF3 or He. Upon absorption of neutrons, such gases release energetic reaction particles. These particles produce ionizations in the surrounding gas which are detected by appropriately biased electrodes. Other detectors coat the walls of the ionization chamber with a solid neutron active material such as 6Li, 10B or 235U. These materials also absorb neutrons and release particles which produce ionizations.
More recently, solid state neutron detectors have been employed that detect electron-hole pairs that cross a semiconductor junction. The electron-hole pairs are produced by reaction particles formed as a result of neutron absorptions within films or dopants of neutron active material incorporated within the detector. The use of silicon carbide (SiC) Schottky diodes as a solid state radiation detector for the measurement of charged particle ionizing radiation is also known to provide benefits over other types of radiation detectors (e.g., ion chambers GeLi detectors, etc.), particularly in high temperature and high gamma radiation environments. Since the silicon carbide detectors are very small, they can be installed or inserted into areas where other detector types would not fit. While the current embodiments of silicon carbide detectors will produce a signal proportional to incident gamma radiation, the signal response is very small relative to the response to charge particle impingement on the active region of the device.
There are applications where the intensity and energy spectrum of a gamma radiation field in a high temperature or limited access area are of importance. An example of this situation is the radiation surveillance needed to characterize the radiation fields surrounding and inside the damaged reactors at the Fukushima site. This invention provides an improved silicon carbide radiation detector design, capable of all the current benefits associated with Schottky diode solid state radiation detectors, that includes a modification that enhances the ability of the detector to detect and characterize the energy of the incident gamma radiation from the radioactive isotopes most important in nuclear power generation.